In recent years, illumination instruments (e.g., LED light bulb) comprising a light source device using an LED have been used from the perspective of energy conservation. However, there is an issue in light source devices using an LED in that an angle of light distribution is small due to the structure, directivity of emitted light thereof, or the like. In this regard, various light emitting devices having a configuration to improve light distribution characteristics and illumination devices using the same have been proposed.
For example, Patent Literature 1 discloses that intense light can be radiated in a direction that is perpendicular to the axis of a substrate to broaden an irradiation range (light distribution region).
FIG. 8 is an enlarged perspective view of essential parts of a reflector used in a conventional illumination device disclosed in Patent Literature 1.
As shown in FIG. 8, a reflector 100 of a conventional illumination device is provided with a plurality of LED light sources 101, a heat dissipation section having a light source mounting surface on which the plurality of LED light sources 101 are provided in a circular shape, a cylindrical protruding section 102 that protrudes out in a direction of light emission from a center section of a light emitting surface of the LED light sources 101, and a reflection surface 104 on which light extraction windows 103 matching the position and shape of the LED light sources 101 are provided.
Light can be reflected with the protruding section 102 that protrudes out in a direction of light emission from a light emitting surface of the plurality of LED light sources 101 to emit light in a direction which is different from the direction of light emission. Thus, it is possible to broaden light distribution of an LED light bulb with a simple configuration of comprising the reflector 100 having the protruding section 102 in the middle.
FIG. 9 is a cross-sectional view of essential parts in a conventional light emitting device disclosed in Patent Literature 2.
As shown in FIG. 9, a conventional light emitting device 200 has a polygonal columnar structure 204 that penetrates through and protrudes out from a center section of a wiring substrate 202 on a metallic section 201, a light source section, which is provided so as to surround the columnar structure 204 and comprises a plurality of LED chips 203 as a plurality of light emitting elements, and a light converting member 205, which is provided so as to surround the columnar structure 204 and the plurality of LED chips 203 and absorbs at least a portion of light emitted by the plurality of LED chips 203 disposed on a side surface of the columnar structure 204 to emit light whose wavelength is converted.
The conventional light emitting device 200 can reduce unevenness in illuminance of light on an irradiated surface while retaining light distribution controllability by using an optical element.
FIG. 10 is a side view of a conventional marker lamp disclosed in Patent Literature 3.
As shown in FIG. 10, a conventional marker lamp 300 comprises: a substrate 301; a light emitting diode element 302 which is erected on the substrate 301 and has a large area of light distribution so as to surround a light axis; a light controlling member 303 that allows light on the light axis of the light emitting diode element 302 to linearly propagate without being obstructed and reflects radiated light in a peripheral section of the light axis in a substantially orthogonal direction; and a translucent globe 304 accommodating the substrate 301, the light emitting diode element 302, and the light controlling member 303. It is possible to readily obtain desirable light distribution that is readily visible without using a plurality of light emitting diode elements 302.